THE GARDEN AT SOUTHERN COMFORT
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Two
fine Trachycarpus fortunei next door to Southern Comfort.
These palms withstand temperatures as low as -15°C. |
A
heated argument:
Exotics
galore. Climate change?
(Christopher Booker's article
in the Sunday telegraph 29 November 2009 - The
Greatest Scientific Scandal of our Generation)
Over
the past years I have heard the words 'climate change' or 'global warming'
whispered in terror at an exponentially increasing rate. Some of my acquaintances
speak as though they were already half-dead from overheating. Later they
recount the holiday spent in Bali frying on a beach at 40°C and then
how dangerous an extra 1°C on top of 20°C would be for the population
of the U. K.. The manifest fact that more and more exotic species of plant
are appearing in garden centres up and down the country is often cited
as incontrovertible evidence of climate change. If to this we add the
encouraging voices of TV's 'instant gardeners' and the popping up of large
exotic botanical specimens in gardens where previously the rose and the
lupin reigned supreme the matter appears to be settled: soon we will have
it even hotter than Bali. The BBC's 'severe weather warnings' every time
a breeze or showers are on the way seems to do little to allay the fears
of much of the population.
Garden centres obviously consider that selling 'plants for a changing climate' or 'kits for a waterless garden' to be a good a good way to boost sales. Best of luck to them, although many 'climate change believers' suggest that not droughts but torrential downpours will be the norm. More worrying for gardeners perhaps is a report in The Daily Telegraph (15 January 2011) that the RHS has joined in the fray. The paper reports that the RHS is advising gardeners to stop watering their gardens, that lawn fertilizers are 'environmentally unsustainable' and that more trees should be planted in order to 'suck up carbon dioxide'. This all seems a long way removed from advising on how best to care for plants. I am glad that I chucked in my membership some years ago because the chillingly cold truth is that rigorous scientific evidence for man's effect on global temperature rise is simply not available. The only sure thing is that temperatures have been very much higher in the past - evidenced by frozen mammoth remains surfacing in Siberia as the permafrost retreats - and that the role of carbon dioxide as a 'greenhouse gas' is dwarfed many times over by atmospheric water vapour whose 'greenhouse effect' is enormous. I am mentioning all this as an introduction to explaining why I think we observe more and more 'exotics' in British gardens.
The first and most obvious reason for the explosion of exotics in U. K. gardens is that gardeners, amateur gardeners in particular, are becoming more knowledgeable. Books, TV programmes and now the internet have made the average gardener both more savvy and more adventurous. Think of the late Christopher Lloyd, Will Giles, Abbotsbury and the jungle at Heligan. Where previously a timid gardener might have poked an Agave into a heavy clay soil in a shady corner and left it to fend for itself today he will seek out a prime position for it on a sunny south-facing bank and give it the best he can in terms of well-drained soil and shelter. Not all books, TV programmes and internet pages are correct however, and it does require an extra degree of finesse of judgement to distinguish between the well-informed expert and the populist dilettante. Many very cold-tolerant plants have the very reverse reputation and it is only recently that this and similar information is beginning to trickle through to the gardening fraternity.
A few examples here would be in order. The ‘Great Bible of Gardeners’, the RHS Encyclopedia of Garden Plants (1966 edition) is most certainly not a book written by dilettantes but it lists Agave americana and A. parryi as tolerant of temperatures down to 5°C and A. utahensis to 10°C whereas the authoritative Agaves, Yuccas and related Plants by Mary and Gary Irish lists them as tolerant to -9°C, -29°C and -23°C respectively. Furthermore they list as many as 20 Agaves which are tolerant of temperatures lower than -10°C! Hmmmm... It would therefore appear that if provided with the appropriate summer temperature, sufficient light and suitable soil some of these plants would be fully hardy not only in the U. K. but also in Eastern Europe. There is a similar story with Aloes where, for example, some forms of Aloe variegata tolerate temperatures down to -8°C (Guide to the Aloes of South Africa, Ben-Erik van Wyk & Gideon Smith, 2nd edn 2003) where the RHS book suggests 10°C. Van Wyk and Smith also note that “Aloe aristata is very cold hardy. It occurs naturally in some of the coldest parts of southern Africa, in the central Karoo and in the mountains of Lesotho.” The RHS book suggests a minimum of 10°C for this plant whereas -10°C would seem more reasonable. There is little wonder that very few gardeners bothered to try these plants outside.
With Palms the matter is no different. The now very popular Jelly Palm Butia capitata (RHS minimum - 0°C for short periods only) is described as follows by Robert Lee Riffle and Paul Craft (An Encyclopedia of Cultivated Palms, 2003): “being adaptable to zones 8 through 11 in drier climates” i.e. to temperatures down to minus 12.2°C. Phoenix canariensis (the Canary Date Palm) takes similar temperatures when its minimum is given as 10° to 16°C by the RHS Encyclopedia. More of these examples can easily be found. Again, a very large Hmmmm….
The second reason is that exotic plants are both more widely available and much cheaper than they were as little as ten or fifteen years ago. This encourages experimentation by lowering its cost. It has certainly made me far less nervous when trying out something new.
Thirdly and perhaps very significantly, a large exotic planted one year may not live to see the following year or, if it does, it may be in rapidly declining health and size after a typical U. K. winter. As observers, all we know is that it has been planted by somebody in his garden – we do not know when (perhaps yesterday?) nor do we know what will happen to it during the coming winter – and we likely to assume that it has been growing in that position for some time and will continue to do so successfully in the foreseeable future. I have heard of a man who bought Bismarckias several years in a row in order to replace the previous year's defoliated and probably rotting stumps. Bismarckias are not cheap plants. I suppose you could call this 'extreme bedding' in the manner of 'extreme sports'. The plants we see and admire are often the ones which have not (yet) imploded or undergone wintertime meltdown.
Another fairly common reason for the increasing number of exotics in our gardens is the enthusiasm of some garden centre and nursery staff who, as already mentioned, talk customers into buying often unviable exotics on the grounds that 'climate change ensures that soon it will be much warmer' (I wonder when; perhaps next month?). Most people do not need much convincing and are happy to walk away with plants that remind them of their last holiday in the Caribbean. The following year they may be back for replacements or may soon begin to treat such plants as annual bedding.
There are other factors which may have more local effects. I am thinking in particular about the 'urban heat-island effect' (this refers to the way in which large agglomerations tend to produce local heat). The higher the temperatures of the insides of the buildings, the higher become the temperatures outside - all other things being equal, of course. London is often quoted as a model example but this effect is present in all urban areas of substance. Over the years - certainly over the last fifty or so years - with the increased levels of heating the urban heat island effect is bound to have become more significant and has enabled slightly more tender plants to grow in places where none grew before.
One final word of caution. The unwary may suggest that early-flowering varieties, with which they are unacquainted, indicate that the temperature must be rising. Such comments have often been made to me when visitors noticed early-flowering Narcissi in spring. In fact, early-flowering in many spring plants may well be the result of a bad previous summer and autumn (with lower temperatures) rather than of higher overall temperatures. This was certainly the case at Southern Comfort at the beginning of 2009. Indeed, the flowering of Narcissi seems to be brought on by by cold spells rather than by warm ones.
Even if we treat some of the predictions of temperature rise seriously the rate of increase is minute in terms of its effect on plant life - a rise of a fraction of a degree in our lifetime is hardly a reason to worry about what we are going to plant in our garden in ten years time, let alone next season. Some gardening web sites even seem to present a picture of global warming as a fait accompli. The whole matter is no less than a contagious mass hysteria based on a deep guilt about being human and breathing out carbon dioxide. As for me, I would welcome a few degrees of warming but I would be a fool if I put my money on it.
Yet there is another side to this peculiar 'debate'. When I was a schoolboy I was taught about photosynthesis — a process occurring within green plants whereby carbon dioxide and water react together under the influence of sunlight in order to produce carbohydrate and oxygen. The carbohydrate is essential for energy production and growth within the plant and in turn enables animals, all of which are dependent on plants, to exist. In simple terms, CO2 helps the plants to grow. So, within limits, the more CO2 we have in the atmosphere, the better plants will grow. All gardeners ought to take note.
(written March 2009, last revision January 2011)
I have been much encouraged by the large number of people who have been following up the links listed below. The NGS, it would appear, has also jumped on the alarmist bandwagon. In issue 4 (autumn 2009) of their newsletter the NGS has included an article which suggests that when we use peat we increase emissions of carbon dioxide. This is nonsense because all organic plant materials have a similar chemical composition to peat and decompose in similar ways. So using other types of organic compost will have the same effect. Furthermore, it is unsound to say that peat should be left in situ because it absorbs carbon dioxide. Peat either in situ or elsewhere most certainly does not absorb carbon dioxide in any meaningful sense of the word. It is the sphagnum moss growing on top of peat in acid bogs that absorbs carbon dioxide before it becomes itself converted to peat. However, sphagnum moss is not unique in doing this - all living plants do this and most are probably more efficient at it than sphagnum moss. So this is more nonsense. All this is probably quite irrelevant anyway because the relationship between carbon dioxide concentration in the atmosphere and temperature rise is yet to be established (some scientists say that there is very little, or even no simple or direct, correlation) as is the question of whether increases in carbon dioxide are damaging to life on this planet - so far the evidence of the latter points in the opposite direction. |
How can you save the planet? Read our tips here.
Some interesting facts about global warming , climate change & green policy
'What
happened to Global Warming?' is the title of an article which
appeared on the BBC web site in October 2009. A quick and easy
digest stressing the most important fault in the hypothesis of
Global Warming: why do global temperatures not rise as the concentration
of carbon dioxide in the atmosphere rises? "Children
just aren't going to know what snow is." So said Dr David
Viner, a senior research scientist at the climatic research unit
(CRU) of the University of East Anglia in the year 2000. Most
of the world, it seems, believed him then. The tragedy is they
still believe him now. One such incorrect prediction normally
sends the most carefully thought out scientific hypothesis to
oblivion. Rises
in sea level as projected by Al Gore, the IPPC and others suggest
that soon there will be no Bangladesh, no Venice, no Maldives
and no Tuvalu. And also many other places. There will be displaced
'climate refugees' on a biblical scale. The rise in sea levels
is one of the most terrifying predictions of climate change lobby. "The
science is settled" (famous quotation, now a defining act
of faith and belief in anthropogenic global warming). See
what happened at the global warming conference in Poznań,
Poland in December 2008. 650 scientists rejected the man-made
global warming claims! Global
warming is so global that it is also occurring on other planets.
Neptune. H2O
possesses vastly stronger greenhouse gas properties than CO2.
The amount of H2O in the atmosphere is vast in comparison
to that of CO2. No correlation has ever been established
between atmospheric levels of H2O and atmospheric temperature.
Glaciers
retreat when precipitation lessens and their bulk can increase
while their length shortens. Not so long ago there were glaciers
in Scotland and in the Tatra Mountains. Inducing fear in populations is a very effective way of ruling them. The communist régimes worked in this way for decades. More
people die of cold than die of over-heating. There
is more and more evidence that increases in atmospheric CO2
would increase the vigour of plants. Such an effect would be
beneficial by increasing crop yields and by allowing plants
to thrive in areas where previously they struggled. When
permafrost melts evidence of mammoths and other creatures is revealed. The
cost of producing all our energy from windmills would be such
that we would starve (and freeze in winter). The
earth's core itself produces a massive amount of heat which gradually
dissipates at the surface. Geothermal heat keeps Iceland warm,
melts ice caps and heats the Arctic. If stone-age man had cared about the future we would now have a heap of flints the height of Mount Everest. Tectonic
activity is a vastly more significant factor in determining sea
levels than is temperature. Species
have always eventually become extinct. Climate constantly changes.
Sea levels are never constant. A future ice age is a greater threat.
The effects of global cooling would be truly catastrophic. Evidence
from the solar cycle suggests that global cooling is a more likely
scenario than global warming. Global
warming policy is all about power, restrictions on freedom and
big business. The
'hockey-stick curve' was a confidence trick: feed the formula
with random data and it plots the same curve. Al
Gore was simply wrong in the vast majority of his assumptions
and arguments. He could not know less about CO2, polar
ice, weather patterns and climate history. "Why
the EU's climate alarmism is both mistaken and dangerous" The
Met Office is now driven by a desire to show the public that our
planet is overheating and is now unable to to produce an unbiased
weather forecast. This is not surprising because the MET is now
run by a 'eco-looney'. 'Repent now or be damned!' This warning is as old as our civilisation: pestilence, plague, famine, nuclear holocaust, ozone holes, amalgam tooth fillings, global cooling, meteors, bird 'flu', swine 'flu' and now global warming. Christopher
Monckton of Brenchley on the scientific reasons why global warming
is not a global crisis - a short video 'Apocalypse NO': What
would happen if the ice caps melted? Read this. Hoping
that the planet stays warm Fossil
fuels? You may have been conned on this one too. There are some
serious arguments suggesting that petroleum is neither biological
in origin nor will it run out in the imaginable future: If
you don't believe any of this then check it elsewhere on the internet
or any other sensible place. You may well be very surprised by
what you find. And if you still think that humans are responsible
for global warming or that global warming must be a bad thing
you will believe in fairies.
Notes Web
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